User Tools

Site Tools


flashing_led_railroad_crossing_lights_with_a_555_timer_chip

This is an old revision of the document!


Flashing LED Railroad Crossing Lights with a 555 timer chip

Parts list and cost

  • 1k Ohm ($0.02 - $0.09)
  • 2.2k Ohm ($0.02 - $0.09)
  • 3.3k Ohm ($0.02 - $0.09)
  • 4.7k Ohm ($0.02 - $0.09)
  • 10k Ohm (3 x $0.02 - $0.09)
  • 10nF [103] ($0.02 - $0.10)
  • 100uF ($0.05 - $0.15)
  • 1000uF ($0.18 - $0.33)
  • 555 timer IC ($0.13 - $0.25)
  • Red LED (2 x $0.03 - $0.14)

Total cost for one: $2.18

Cost per unit for 50 bulk: $0.58

555 Timer IC

Modes

  1. Astable
  2. Monostable
  3. Bistable (schmitt trigger)
Astable

Monostable

Step by step wiring instructions

  • 555 timer Pin 1: e2
  • 555 timer Pin 1: e22
  • Yellow jumper: left power bus to right power bus
  • Black jumper: left ground bus to right ground bus
  • Black jumper: a2 to left ground bus
  • Jumper: a3 to a7
  • 100uF capacitor: c7 and stripe side in c8
  • Black jumper: a8 to left ground bus
  • Jumper: d3 to f1
  • 10k resistor: j1 to j3
  • Jumper: b4 to f13
  • Red jumper: c5 to right power bus
  • Jumper: d5 to h2
  • Jumper: g4 to e7
  • 1k resistor: g2 to g3
  • 4.7k resistor: j8 to j12
  • 2.2k resistor: h14 to h18
  • Black jumper: j18 to right ground bus
  • Red LED: h12 to h13 (cathode; flat side)
  • Red LED: i13 to i14 (cathode; flat side)
  • Black jumper: Arduino GND to left ground bus
  • Red jumper: Arduino 5V to left power bus
  • Flasher should be working.
  • Remove red jumper from Arduino 5V
  • Remove red jumper between left and right power bus
  • Black jumper: a22 to left ground bus
  • Jumper: d23 to f20
  • 10k resistor: h20 to h22
  • Yellow jumper: j20 to nothing
  • Yellow Jumper: d24 to right power bus
  • Red jumper: a25 to left power bus
  • 10nF capacitor: j25 to j27
  • Black jumper: i27 to right ground bus
  • 1000uF capacitor: h24 and stripe side in h27
  • Jumper: g23 to g24
  • 10k resistor: j22 to j23
  • Red jumper: g22 to left power bus
flashing_led_railroad_crossing_lights_with_a_555_timer_chip.1503813968.txt.gz · Last modified: 2017/08/27 06:06 by adam